Ariel Castro was serving life plus a thousand years for holding three Cleveland women hostage in his home for a decade, repeatedly raping them and fathering a child by one of them. The 53-year-old Castro was found dead in his cell with a sheet wrapped around his neck, and his pants and underwear around his ankles.

A report released today by the Ohio Department of Rehabilitation and Corrections says it’s possible he was attempting auto-erotic asphyxiation – an act by which people achieve sexual satisfaction by briefly choking themselves into unconsciousness. Officials say no suicide note was found, and multiple evaluations of Castro found no tendency toward suicide.

The report also says Castro was not shown a mandatory suicide-prevention video when he arrived at the Orient Correctional Institute in August. It said he had expressed concern that his food was being tampered with, but the investigation said that was unfounded.

Additionally, the report says an ambulance was significantly delayed in getting to the prison after Castro’s body was found, but says there’s no indication that affected the outcome.

The findings are similar to those in the suicide of death row inmate Billy Slagle of Cleveland in August. Guards in that case were suspended as well.